In a fuel injection apparatus of the type disclosed in the publication "Motorrad" 32/1956, page 1038, a suction valve is arranged on the side of the pressure chamber opposite the pump piston to introduce fuel into the pressure chamber during the return stroke of the pump piston. It is a disadvantage of this arrangement that the control of the fuel introduced into the pressure chamber is not reliable, particularly in a small high-speed engine where only a very low pressure chamber volume of about 1 to 2 mm.sup.3 per piston stroke is provided for metering a minimum possible amount of fuel. It is also known from Bosch publication VDT-UPB 001/10 5.53 to lap the pump piston for fuel injection. Such lapping requires a very high finishing accuracy involving a highly complex procedure particularly with small piston diameters. In addition, with the diameters becoming progressively smaller, leakage losses increase disproportionately when referred to the volume of the pressure chamber. As a result, apart from being complicated and expensive to manufacture, these apparatus do not provide sufficiently accurate control possibilities in small high-speed engines.